Jerry Fisher revealed to Harold that his father was a professional boxer, which the father did not want, as he felt that his profession was not respectable. But Harold did not think so and, in fact, enjoyed boxing as a sport. This knowledge made the father decide to fight again, which shows that he was a practical man wanting to keep his family members happy.
It also helped him to earn some money, as it was needed for Harold’s education. Thus, Harold has the value of respecting his father’s actual profession, while his father displays a caring attitude for Harold.